1. Field of the Invention
This invention relates in general to inductors for use in integrated circuits, and relates more particularly to integrated circuit inductors having magnetic cores.
2. Description of the Related Art
Inductors are used in a wide range of signal processing systems and circuits. For example, inductors are used in communication systems, radar systems, television systems, high pass filters, tank circuits, and butterworth filters.
As electronic signal processing systems have become more highly integrated and miniaturized, system designers have sought to eliminate the use of relatively large auxiliary components, such as inductors. One approach to eliminating the use of actual inductors in signal processing systems is to simulate inductors using active circuits, which can be easily miniaturized. Unfortunately, simulated inductor circuits tend to exhibit large parasitic effects and often generate more noise than circuits constructed using actual inductors.
When unable to eliminate inductors in their designs, designers have sought ways to reduce the size of the inductors that are used. For example, inductors are miniaturized for use in compact communication systems, such as cellular phones and modems. These miniaturized inductors typically comprise two-dimensional spiral inductors that are fabricated on the same substrates as the integrated circuits to which they are coupled. Although these two-dimensional spiral inductors can be fabricated using conventional integrated circuit manufacturing techniques, they typically take up a disproportionately large share of the available surface area on an integrated circuit substrate.
For these and other reasons, there is a need for the present invention.